Insulator.



R. FRIESE.

INSUA'1'0B.1

Arrucn'xox Hmm JAI. 1, 1911.

1,107,281 Patented Aug. 18, 1914 vvmwasses KNVENTGR UNITED STATES PATENT OFFICE.

ROBERT FRIESE, OF CHARLOTTENBURG, GERMANY, ASSIG'NOR T0 SIEMENS-SCHUCK- ERT-WERKE G. M. B. H., OF BERLIN, GERMANY, CORPORATION OF GERMANY.

INSULATOR.

Specification of Letters Patent.

Patented Aug. 18, 1914.

Application filed January 191i. Serial No. 60?.,435.

Condensers and Known contara g' 'in "i "l he descVA ycmg to this known l electrically-Eoncould c lod oni' A primar my invention is to forme not i casio: a l cheaper mode ac insulators havin. the

act n of con y dcnscrs, insulators cescriloed Sonie illustrative enihodiinents of iny invention are represented by Way of example in the acconipanying5 drawing, wherein:-

Figures l and 2 show parts of a condenser in cross-section and longitudinal section, respectively; Figs. 3 and i are longitudinal section and cross-section, respectively, showing a leading-in insulator having the action of a condenser, and Fig. 5 is a section showing a condenser comprising electrically conducting intermediate layers not extending to' the outside of the saine.

Referring to the drawing, designates the outer coating, .7), the inner coating, s1, s2 electrically conducting layers, and (Z1, (Z2 the dielectric of the condensers or leading-in insulators for high tensions.

ln condenscrs and leading-in insulators as shown in Figs. 3 and 4 there is the danger that as the tension increases sparks will pass between the points s1 and 82. This danger is eoiuiucti are the the particularly great When the insulators employed at places Where the surface oi dielectric is subjected to the iniiuence of Weather or moisture.

i-ccording to my invention, order to prevent the insulators eine ruptured loy the high tension do not alloiv the electrically comilucting intermediate layers to extend quite to the surface the dielectric. as clearly shown Fig. En ierA is 'has been found that the electricany condncti u intermediate layers serve their onvv when they possess little c Wliicl ploy noon as insuiat` intermediate lay s ally require ne o f ness. Linking th s leading-in insulators of the sented in -EEigs. 3 and el, for exam? e, i formed oit' concentric glass or porcelain tunes provided with thin metallic deposit as coating. is spaces or gaps between the individual tubes cannot be avoided in such insulators I prefer to employ an electrically conducting material between the coatings, e. g. tin-foil, powdered metal, powdered carbon and the like, Which may he 1forced into the gaps or spacesV between the coatings, so that after its insertion it forms a more or less solid conducting mass. Condensers, insulators and other apparatus having the action of condensers not of vtubular shape can of course be made in asimilar manner.

The above mentioned substances ror electrically connecting adjacent coatings, particularly metallic powder and powdered carbon, may, when suitable, themselves form electrically conducting intermediate layers, so that connecting'coatingsor coverings on the surfaces of the dielectric are unnecessary, because the grains which are close to gether and contact with the surfaces of the dielectric are to be looked u on more or less correctly as electrically con ucting coatings. As the resistance of the electrically conducting-intermediate layers maybe'very considerable without the layers ceasing to serve their purpose, they do not necessarily have to be composed of metal, but it is frequently preferable to make them of substances known briefly as bad conductors. It lhas been found, for example, that not only gypsum containing electrically conductingadmixtures but gypsum itself without anyspecial admixture of electrically conducting substances may be employed with complete success for the electrically conducting intermediate layers. Admixtures of powdered carbon or metallic powder and the like can be used to assure the `small requisite-ccnductivity 'of gypsum or cement, and particularly also certain salts, such as .chlorid of sodium or chlorid of magnesium. Under certain circumstances solutions or@ liquid acids may also be employed. In general, on account of the but small requisite con# ductivity, the intermediate layers may Vbe made of conductors of the second class with y and without admixtures of conductors of the rst class.l

The condensers or insulators according to my invention may be shaped according to the circumstances in eachcase. essential that-the dielectric-layers which are not perfectV non-conductors of `electricity be separated by intermediate layers which in comparison with the former possess a materially greater conductivity, even if this be .small in itself. These relations may briefly be stated by saying that the dielectric-layers must be separated by intermediate layers of onl small conductivity.

- (yondensers/ of the type described possess special advantages-with regard to the mode It is only by which they can be manufacturedf For example, they can be made by employing as the material either for the dielectric or for the conducting intermediate layer a liquid, or aA substance which'softens when heated.

If such a substance be-used for the dielectric, the plastic or liquid dielectric can be poured or pressed into the rigid, electrically conducting intermediate layers, where it will solidify while if such a substance be used for the intermediate layers it can be poured into suitable cavities in ther rigid dielectrid.

` air in the interior of the condensers or the like can be completely avoided.

l claim Y As a new article of manufacture, an insulator having the action of a condenser, comprising a plurality of layers of a solid dielectric of varying lateral extension, alternating with a plurality of layers of a plastic material of small electric conductivity adapted to solidify between said dielectric layers.

In testimony whereof l have signed my name to this specilicationin the presence of two witnesses.

ROBERT 'FRIESE Witnesses:

HENRY HASPER, WOLDEMAR Hawai, y

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